I'd say not having the man with a gun pretty much instakill you upon sight. I think it'd be nice to give the player a little time to react once he starts shooting so you can blow the whistle and stun him long enough to get away. Also, if Maria is going to pursue the player so relentlessly, maybe adding in a way for the player to incapacitate one of the two bad guys would make things more fun. There's just A LOT of ground to cover, drawers to open, places to search, etc., so managing to stay away from one of the baddies only to run right into the other one makes it feel kind of rigged and not worth repeating over and over again.